Conventionally, a motor drive apparatus is known, in which AC power from an AC power supply is converted into DC power by a rectifier, and in which the DC power is further converted into three-phase AC power by an inverter, and then the three-phase AC power is supplied to an AC motor (see, for example, PTL 1).
Further, on the other hand, a motor drive apparatus is known, in which a DC power supply is connected to an inverter, and in which DC power from the DC power supply is converted into three-phase AC power, and then the three-phase AC power is supplied to an AC motor. The motor drive apparatus of each of these types is adopted, for example, in such a case of driving a compressor motor of a vehicle air conditioner mounted on an electric vehicle not equipped with an engine.
Further, one-pulse control is conventionally known as one of the control methods for improving the voltage utilization factor of an inverter. The one-pulse control is a control method in which, during one electrical angle cycle, a positive rectangular pulse voltage and a negative rectangular pulse voltage are applied to each switching element corresponding to each of the three phases (see, for example, PTL 2).